Add measurement noise

[Ji Chen]

Hi Ray,
   I'm tring to do state estimation with measurements V and I in rectangular 
form. Measurement noise is simulated as independent zero-mean Gaussian with 
standard deviation per real component 0.01 and 0.02 for voltages and currents, 
respectively. Ir and Vr are real parts of I and V respectively. 
    I'm not sure if the following codes are right. What's more, how to deal 
with the imaginary componets?


Ir=Ir+0.02.*randn(length(Ir),1);
Vr=Vr+0.01.*randn(length(Vr),1);


Best Regards！